Lankhmar

City of the Black Toga
Hobbits, elves and dwarves populate the White Box milieu because of the popularity of the fiction of J.R.R. Tolkien, but in his Appendix N of the Dungeon Master's Guide, Gary Gygax lists Fritz Leiber's Fafhrd & Gray Mouser series as one of the "most immediate influences" on his fantasy work. The series Mr. Gygax refers to includes five books published in 1968 (and one each in 1977 and 1988 which were published afterwards). The stories are set in the fictitious Lankhmar, City of the Black Toga and surrounding areas. The population is primarily human, although various aliens and original races do make appearances. Nehwon, the world setting, which at times is described as a bubble floating through space, is a magical place where sorcerers cast electrical bolts and visitors from far away dimensions and other worlds frequently intrude.
Lankhmar itself is described as a smokey (City of Ten Thousand Smokes), misty (Swords in the Mist!) place ruled by a pampered overlord who abhors human hair and demands all his servants (and concubines) be completely shaved - even their eye lashes. Various guilds exercise power over the many trades, markets and professions, including a prominent thieves guild. Religion in Lankhmar is reflected in the various temples along the Street of the Gods. As religions prosper they move up the street and as they decline they move down the street, presumably occupying various ancient temple structures along the journey.
The Swords... tales follow the antics and adventures of two heroic rogues of dubious ethics, Fafhrd, a tall northern barbarian warrior and (the) Gray Mouser, a short southern swordsman and amateur magician. Both characters are complex in their personality, relationships, motivations and interests. The two are usually fast friends, but do experience occasional falling outs that result in heated rivalry. The stories contain much humor and many turns of plot and are stylishly written. I consider them among the best in the genre.
Both Fafhrd and Gray Mouser are frequently in the service of their respective magical patrons - Ningauble of the Seven Eyes and Sheelba of the Eyeless Face - who are themselves sometime allies and sometime rivals each pulling their cohort in opposite directions. Two Sought Adventure, the first published story to feature the duo, was written in 1939 and appeared in Unknown, a magazine which published pulp fiction with a bit more emphasis on humor than Weird Tales and Astonishing Stories (which also published Conan stories by Robert E. Howard - another major influence on Mr. Gygax).
Besides serving as inspiration for White Box, Greyhawk and the Advanced Game, the Swords... stories of Fritz Leiber have been the basis of several Lankhmar settings for various rules including White Box (Supplement IV), Advanced (TSR), RuneQuest (Mongoose), Savage Worlds (Pinnacle Entertainment Group) and Dungeon Crawl Classics (Goodman Games). Two of these are still in print (Savage Worlds & DCCRPG). Lankhmar has unofficially served as a model for many other hobby products (for example - Judges Guild's City State of the Invincible Overlord which includes locations such as the Silver Eel tavern, Cheap Street and the Park of  Pleasure).
White Box is a conglomeration of a number of influences affecting each of its two principle authors (and probably several early players as well). Chief among them is the city of Lankhmar as can be seen in the adventure stories of Fafhrd and (the) Gray Mouser and played out in campaigns bearing the official name "Lankhmar" and those which merely borrow from the memory of those who have read the Swords...
Bored and penniless, adventurers everywhere seek profit and glory just like Fafhrd and Gray Mouser. They consult their wise and powerful patrons, vie with their rivals and frequently cause much collateral mischief in pursuit of wealth and fame, often with the best of intentions, but occasionally only for the most selfish of motives and we, the witnesses to these tabletop adventures, marvel at the surprises, humor and excitement found along the way...with no little thanks to Lankhmar.